ML20010E117

LER 81-041/01P-0:on 810824,stack Gas Pump a Tripped Causing Stack Gas Low Flow Alarm to Annunciate.Caused by Thermal Overload Due to Pump Binding from Brittle Carbon Vanes.Stack Gas Sample Pump Rebuilt

ML20010E117
Person / Time
Site:	Oyster Creek
Issue date:	08/26/1981
From:	JERSEY CENTRAL POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20010E115	List: ML20010E114 ML20010E117
References
LER-81-041-01P, LER-81-41-1P, NUDOCS 8109030113
Download: ML20010E117 (2)

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OYSTER CREEK NUCLEAR GENERATlhG STATION Forked River, New Jersey 08731 Licensee Event Report Reportable Occurrence No. 50-219/81-41/0lP Repart Date August 26, 1981 Occurrence Date August 24, 1981 Identification of Occurrence The Stack Gas activity was not continuously nonitorod as required by Technical Specification 3.6.A.3 due to a trip of the "A" Stack Gas Sanple Punp.

This event is considered to be a reportable occurrence as defined in the Technical Specifications, paragraph 6.9.2.A. (2) .

Conditions Prior to Occurrence The plant was in the refuel node at the tine of the occurrence. Reactor tenpera-tures were below 212 P and the reactor was vented.

Description of Occurrence On Monday, August 24, 1981, at approxinutely 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> the stack gas 1cu flow alann annunciated in the Control Roan. An operator was dispatched to investigate the problan and found the "A" Stack Gas Pump tripped. The "B" Stack Gas Pump was placed in service but would not maintain a high enough vacuum to clear the stack gas low _ Sow dann. At 0230 the following norning, instrumentation personnel cleared the alann by tightening the "B" punp suction piping fittings and by increasing pump flow.

Apparent Cause of Occurrence The "A" Stack Gas Sample Punp tripped on thennal overload because of pump binding. This binding occurred because the pump's carbon vanes became brittle and failed during the pump's nonnal operation.

Analysis of Occurrence A review of the Stack Gas Radiation Monitor Recorder shami the levels in both nonitor channels to be constant (70 CPS) before and after this event. In a further effort to determine if excessive stack gas releases might have occurred during the event, a review of the Reactor Building ventilation exhaust radiation nonitor recorder showed that the levels in both channels were relatively constant with no spik i m .

8109030113 810826 PDR ADOCK 05000219 S PDR V _ _

Reportable Occurrence Page 2 Report No. 50-219/81-41/0lP Tne Augnental Off Gas System, the mechanical vacuum punp and the steam packing exhauster were secured during the event, and, therefore, could not provide additional radiological influents to the stack. Based on these considerations the safety significance of this event is considered muumal.

Corrective Action The stack gas sanple flow was returned to nonlul by placing the "B" Stack Gas Sanple Punp in service. The "B" pump's suction fittings had to be tightened, and punp flow had to be increased, in order to clear the stack gas lcw flow alann. The "A" Stack Gas Sample Punp was rebuilt on August 26.

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